So after reading this thread we are sold on getting Dolphin Discover, especially since we have an older pool built before any fancy schmancy automatic cleaners were about.
One lingering question I have is how is this bad boy with nuts? we have a large oak near our pool and it likes to drop acorns in the pool quite often, we had a Zodiac Baracuda but this stole power from the single skimmer the pool was originally built with and caused water issues (House was a rental and had a company managing it). The treads would also get bound up and it would jump it's tracks and just quit (according to the renter).